SES Mahakam Lakes, Indonesia

The Mahakam Lakes in East Kalimantan, Indonesia, represent a national priority peatland wetland facing severe degradation from upstream industries and community activities. The scientific problem is the persistent failure of conventional technocratic approaches to address complex water quality challenges in tropical lowland development. This study integrated hydrochemical analysis with community perceptions using a mixed-method approach: quantitative water quality monitoring at seven stations during 2023 and 2025, and qualitative interviews with fishing communities. Hydrochemical analysis revealed "ecological shock" with total hardness spikes from <10 mg·L⁻¹ in 2023 to 125–220 mg·L⁻¹ in 2025, and elevated sulfur reaching 2.1 mg·L⁻¹ at river inlets. Community perception data identified a fundamental mismatch: residents normalise degradation as natural seasonal cycles, triggering autonomous chlorine use evidenced by residues up to 0.57 mg·L⁻¹ in settlement areas. This creates maladaptive feedback loops where household coping strategies exacerbate pollution. Current technical monitoring fails to address the "shifting baseline syndrome" among water users. Sustainable management requires hybrid governance synchronising scientific monitoring with local ecological knowledge, fostering community-based surveillance, and harmonising formal regulations with customary norms.